Association of caffeine consumption with all-cause and cause-specific mortality in adult Americans with hypertension

Coffee is an important beverage that is widely consumed, of which caffeine is the main active ingredient. However, the long-term relationship between caffeine consumption and mortality in hypertensive patients has rarely been studied. This study analyzed a cohort of 12,093 US adults from the National Health and Nutrition Examination Survey from 1999 to 2018. Caffeine consumption was divided into five groups: no intake, >0 to <= 100, >100 to >300, >300 to >400 and >400 mg/day. Using multivariable-adjusted Cox proportional hazards models, this study performed a 20-year follow-up analysis (1999-2018). In the fully adjusted model, all caffeine consumers had lower all-cause mortality compared with no intake, especially in the >300 to <= 400 mg/day group (hazard ratio (HR) 0.71, 95% confidence interval (CI) 0.60-0.84). The result of restricted cubic spline also showed a nonlinear association between caffeine consumption and all-cause mortality. For cardiovascular disease, mortality decreased only at >400 mg/day (HR 0.63, 95% CI 0.47-0.85). For cancer, diabetes, and kidney disease, only >300 to <= 400 mg/day was significantly associated with decreased mortality: (HR 0.60, 95% CI 0.42-0.67), (HR 0.22, 95% CI 0.07-0.75), and (HR 0.32, 95% CI 0.10-0.96), respectively. Lower all-cause mortality was observed in non-Hispanic White, African American, population aged 40 or above, and people with a body mass index <25 kg/m(2). Our findings indicate a nonlinear association between average caffeine consumption and all-cause mortality, suggesting that hypertensive patients may benefit from moderate caffeine intake.